PROBLEM TO BE SOLVED: To provide an underpants type disposable diaper which allows a wearer to pass easily legs to leg surrounding opening parts, and which is excellent in fitness on a crotch part.SOLUTION: An underpants type disposable diaper comprises: an external body 20 having a girth part T which is annularly continuous and an internal body 10 containing an absorber 13 which extends from an intermediate part in a width direction WD of the girth part T of a front bodice F, to an intermediate part in the width direction WD of the girth part T of a rear bodice B through the crotch part. Parts overlapping the girth part T of the front bodice F and the girth part T of the rear bodice B on the internal body 10 include respectively, junctions 30 jointed to the external body 20 in plural width ranges 17 positioned in the width direction WD at an interval. An area between the width ranges 17 on the internal body 10 is not jointed to the external body 20, and is a width expandable area 18 where a width can be expanded. The external body 20 has a stretchable area which can elastically stretch in the width direction WD by a girth elastic member 25 on an area where the girth part T and the width expandable area 18 overlap.SELECTED DRAWING: Figure 11COPYRIGHT: (C)2018,JPO&INPIT【課題】脚を通しやすいものでありながら、股間部のフィット性に優れるものとする。【解決手段】環状に連続する胴周り部Tを有する外装体20と、前身頃Fの胴周り部Tの幅方向WD中間から股間部を経て、後身頃Bの胴周り部Tの幅方向WD中間まで延びる、吸収体13を含む内装体10とを備え、内装体10における前身頃Fの胴周り部T及び後身頃Bの胴周り部Tのそれぞれと重なる部分は、幅方向WDに間隔を空けて位置する複数の幅方向範囲17に、外装体20に接合された接合部30をそれぞれ有し、内装体10における幅方向範囲17の間の領域は、外装体20に接合されず、幅が拡大可能である拡幅領域18となっており、外装体20は、胴周り部Tと拡幅領域18とが重なる領域に、胴周り弾性部材25により幅方向WDに弾性伸縮する伸縮領域を有するパンツタイプ使い捨ておむつである。【選択図】図11
